Valve guide of internal-combustion engines



July 2, 1946.

H. N. CHARLES VALVE GUIDE OF INTERNAL-COMBUSTIN ENGINE Filed Oct.. 11, 1944 Patented July 2, 1946 VALVE GUIDE OF INTERNAL-COMBUSTION ENGINES Hubert Noel Charles,

England, signor to The Limited, Northeld,

pany lland Austin Motor Com: Y

Birmingham, Enzl Application October 11, 1944, Serial No. 558,191

In Great ,9 Claims. l

The invention relates to valve guides o'f internal combustion. engines, and has for its object to effect improvements therein chiefly with a view to reducing valve noise.

It is well known that, if the valve guide clearance is made very small, the valve stem is liable to stick due to its lateral expansion when heated, because the valve guide, being set in the cylinder head or cylinder block, cannot expand freely in a lateral direction, and furthermore its temperature will be governed by that of the cylinder head or cylinder block which will, under running conditions, be less than that of the valve stem,- especially if, as is often the case, the guide is in contact with cooling liquid. As a consequence it has heretofore been found necessary to allow considerable freedom of the stem within the guide, with the result that a good deal of unwanted noise is produced and leakage of oil and gases between the valve stem and the guide may take place.

Britain September 6, 1943 (CL 12S-188) D. c is the valve stem.

In order to avoid the above disadvantages, and

according to thisinvention, the valve guide is made in two parts, one of which is an inner partv set in the cylinder head or Vcylinder block (as the case may be) in the usual manner, except that it may be arranged to project a short distance from the outer surface of the part of the engine in which itis set. Free or normal clearance C is allowed between such inner part of the guide and the valve stem passing through it. The other part of the valve guide is an outer part so positioned that it is free to expand laterally, for the reason that it is not ttedwithin the cylinder head or cylinder block. It is preferably placed outside such cylinder head or cylinder block being spigoted onto the aforesaid projecting portion of the inner part of the guide.

The outer part of the guide may be held in place in any manner which permits of its free lateral expansion, but preferably it has a flange formed at its inner end on which the valve spring bears, the flange acting as the inner locating washer for the spring, and also as the means for keeping the outer part of the guide in place. The clearifnce between such outer part of the guide and the valve stem may be much smaller than the usual clearance heretofore provided between valve guides and the valve stems guided therein.

The said outer part ot the guide may be of bronze or rother metal having a higher co-eiilcient of expansion than the valve stem, and the outerpart will tend to become of the temperaof the valve stem andjwill expand accordingly and maintain, or even slightly increase, the clearance, as the valve stem heats up.

formed of bronze or other metal having a relaf um@ neat from the upper end The smallness of the clearance between the valve stem and the outer part of the guide secures the double advantage of reduced noise without tendency of the valvestem to stick and lessliability for oil and gases to leak along the guide.

A convenient embodiment of the invention is described with reference to the drawing herewith which is a vertical section 'through a cylinder head of an internal combustion Aengine and through one of the yvalves thereon In this drawing:

A indicates a cylinder -head of conventional form having inserted therein a valve seat a. B indicates the usual water cooling space. C is one of the valves also of conventional form being impelled towards the \valve seat a by coil springs E is the lower or inner portion of the valve guide and it is set as tight lit in a hole bored to receive it in the cylinder head. The portion E of the guide has a short portion e extending above the top of the head.

'I'he stem c is arranged to have free or normal clearance C in the guide portion E, the clearance being sufllcient to ensure that lateral expansion of the stem under working conditions will not cause sticking of the stem in the guide.

`The guideportion E may iron, steel or other metal.

F is the upper portion of the valve guide being tively high co-eilicient of expansion. It is bored to receive thevalve stem as a relatively close but free sliding fit. It is recessed at f to receive the upper end e of the guide portion E as a good fit; and the recess f is vcarried up a short distance beyond the portion e so as to leave an annular recess or heat break G between the top of the portion E and the top of the recess f.

A stepped flange j is formed on the lower end of the guide portion F, the springs D bearing down thereon and being located thereby. At the of the stem c there is fitted the usual stepped washer H and split cotters h.

The lower Ypart of the valve stem c will receive heat from the valve and consequently its temperature will be relatively high, but owing to its free vclearance C' in the guide portion E, it can expand freely without danger of sticking in the guide. The guide portion F will receive heat from the upper part of the stem; but owing to its relatively high co-efiicient of expansion it will always leave a working clearance and, owing to the "heat break G', it will receive comparatively guide portion E. As a result be formed of cast greatly reduces mounted 'in a manner to allow expansion and having a clearance less than thatA leave a space between 3 the stem c and the guide so ensuring a oil and gases. very accurate control over the movements of the valve, so that it will come accurately on to its seat which noise.

Having fully described my invention what I claim and desire to secure by Letters Patent is:

l. A valve guide of an internal combustion engine said valve guide comprising two separate parts,l one of said parts being an inner par-t set in a fixed part of the engine and having the usual clearance between its inner surface and the stem -of the valve with which itis associated, and the' other of said parts being an, outer part mounted in a manner toallow of its free lateral expansion and having a clearance less than thatof the said inner part, an axial recess in the inner end of said outer part and an extension of said inner part entered into said recess.

2. A valve guide of an internal combustion engine said valve guide comprising two separate partsi in a usual fixed part of the engine and havingthe4 clearance between its inner surface and the stem of the valve with which it is associated, and

one of said parts being an inner part settheother of said parts being an outer part of its free lateral of the said inner part, an 'axial recess in the inlner end of saidouterpart and anextension of said inner part entered into said recess, said extension being shorter than said recess so as to the end of the recess and the end of the said extension.

3. A valve guideof an internal combustion engine said valve guide comprising two separate parts, one of said parts being an inner part set 1n a xed part of the engine and having'the usual lclearance betweenits inner surface and the stem of the valve with -which it is associated, and the other of said parts being an outer part mounted in a manner to allow of its free lateral expansion and having a 'clearance less than that of the said inner part', said inner and outer parts being- 'spaced sufliciently to form `aheat break, and van external annular ange atthe inner endv of the said outer-part acting as anabutment for the usual valve spring or springs,

4. A` valve guide of an internal combustion engine` said guide being transversely divided into two separate parts both directly surrounding the valve stem and slightly spaced from each other to form a heat break, the one part being an inner part, that is to say nearer to the valve head than is the othervpart and sei; in a xed part of the engine, and having the usual clearance between it and the surface of the valve stem, the other of said parts being an outer part mounted in a manner to allowof its free lateral expansion and having a clearance less than: that of the said inner part.

5. A valve guide of an internal combustion engine said guide being transversely divided into two separate parts both directly surrounding the l is vthe other" part inner part, that is to say nearer to the valve head than is` the vother part and set in a xed part of the engine,- and having the usual clearance between it and the surface of the valve stem,

'the other of said parts being an outer part mounted in a manner to allow of its free lateral expansion and having a clearance less than that of the said inner part, and said outer vpart mounted outside the part of the engine in which the inner part is set.

6. A valve guide of an internal combustion ena gine said guide being transversely divided into two vseparate parts both directly surrounding the valve stem and slightly spaced fromv eachother to form a heatbreak, the one part being an inner part, that is to say nearer to the valve heady 7. A valve guide of an internal combustion engine said valve guide comprising two separate parts one of said parts being an inner part set in a ilxed part of the engine, and havingthe usual clearance between its inner surface and the stem of the valve with which it is associated, and the other of said parts being an outer part mounted in a manner to allowy of its free lateral expansion and having a clearance less than that of the said inner part,ian axial recess in the inner end of said outer part and an extension of said inner part entered into said recess.

8. A valve guide of an internal combustion engine said valve guide comprising two separate parts one of said parts being an inner part set in a fixed part of the engine, and 'having the usual clearance between its innersurface and the stem of the valve with which it is associated,. and the other of said parts being an iouter part mounted in a manner to allow of its free lateral expansion and havingva clearance less than that of thel said inner part, an axial recess in' the inner end of the said outer part and an extension of said inner part entered into said recess, said` extension being, shorter than said recess so as to leave a spacebetween the end of the recess and the end of the said extension.

9. A valve guide ofV an internal combustion engine said guide being transversely divided into v two separate parts both directly surrounding the valve stem and slightly spaced from each other to form a heat break, the one partbeing an inner part, that is to say nearer to the valve head than and set in a fixed part of the engine, and having the usual clearance between it and the surface of the valve stem, the other of said parts being an outer part mounted in a manner to allow of its free lateral expansion and having a clearance less than that of the said inner part, and an external annular ange at'the inner end of the said outer part acting as an HUBERT NOEL CHARLES.

usual valve spring or springs. 4 

